1. Field of the Invention
The present invention relates generally to a method and system for sharing a digital rights management file between portable terminals and, more particularly, to a method and system for sharing a digital rights management file between portable terminals, which supports the portable terminals so that they can share and reproduce the digital rights management file during a connected call.
2. Description of the Prior Art
Digital Rights Management (hereinafter referred to as “DRM”) technology provides a continuously management and protection of intellectual property rights of digital contents using encryption techniques. The DRM technology involves safely conveying various contents from a Content Provider (CP) to a user while preventing a user from illegally circulating the conveyed contents.
Such DRM technology makes it possible to protect information through the entire process covering the generation, distribution, use, and discard of digital contents, and enables a user to use digital contents according to the rights given to him/her and protect his/her rights for the digital contents off-line as well as on-line.
In order to use a content to which the DRM technology is applied (hereinafter referred to as “DRM content”) in a portable terminal, a user of the portable terminal must access a content provider server providing the corresponding DRM content, and download the DRM content, metadata, and a license for the DRM content. Here, the metadata refers to data in which information on a DRM content is stored, and the license refers to data that contains a decryption key used for decrypting an encrypted content and specifies content use rights (e.g., number of times, period, etc.).
Once both the DRM content and license are stored in a portable terminal through such a process, the DRM content is available to the user. However, the user may use the DRM content within the limit of the content use rights specified in the license. The license may specify the content use rights by restricting the number of reproductions, the period of use, or the like. More specially, when the license restricts the number of reproductions, the DRM content cannot be reproduced any longer if the number of times that the user has reproduced the DRM content is equal to or greater than the allowed reproduction. That is, when the license restricts the period of use, the DRM content cannot be used any longer if the period of use of the DRM content, specified in the license, expires. Further, when a DRM content for which a license must be acquired is stored in a specific portable terminal, the DRM content is set up in such a manner that it cannot be transmitted to another portable terminal, and even if the DRM content may be transmitted, it is impossible to reproduce the DRM content in another portable terminal that receives the DRM content.
In general, music files, image files, etc. form the majority of DRM contents, and such DRM contents are more valuable when many users share them. That is, users of DRM contents have a strong tendency to strengthen ties and deepen understanding between people by allowing others to share their favorite music or image files. Thus, there is a strong need for a method of legally sharing DRM contents in line with the tendency of users thereof.